Large-sized pneumatic radial tire

Abstract

A large-sized pneumatic radial tire is disclosed. This tire comprises a tread including grooves, a belt composed of a plurality of rubberized layers each containing steel cords, and a carcass of a radial or semiradial construction. The tread includes two half regions divided with respect to a crown center, one of which being a region in a direction of plysteer due to the tire construction and the ground contact reaction force acting to steel cords of at least one rubberized layer disposed near the tread and the other being a region opposite to the direction of plysteer. Reinforcements are provided on walls of tread grooves at kicking-out side of the region opposite to the direction of plysteer.

What is claimed is: 
     
       1. A large-sized pneumatic radial tire comprising a tread including grooves having alternately directed inclined portions at an angle of 30°-90° with respect to the circumferential direction of the tire, a belt composed of a plurality of rubberized layers each containing steel cords, and a carcass of a substantially radial construction; said tread including two half regions divided with respect to a crown center, one of said regions being a region in a direction of plysteer which is produced due to the tire construction and to the ground contact reaction force acting on said steel cord of at least one rubberized layer disposed near said tread and which acts upon the tire, and the other region being a region opposite to the direction of plysteer; characterized by only providing reinforcements on the kicking-out sides of the walls of said inclined portions of said grooves in said region opposite to the direction of plysteer. 
     
     
       2. A large-sized pneumatic radial tire as claimed in claim 1, wherein said reinforcements are provided only on the stepping-in sides of said walls of said inclined portions of said grooves in said region in the direction of plysteer. 
     
     
       3. A large-sized pneumatic radial tire as claimed in claim 1, wherein said tire has an aspect ratio of not more than 0.9. 
     
     
       4. A large-sized pneumatic radial tire as claimed in claim 1, wherein said tire has a ratio of tread gauge to belt total gauge of 0.7-2.5. 
     
     
       5. A large-sized pneumatic radial tire as claimed in claim 1, wherein said reinforcement is so constructed that a wall of said groove to be reinforced is inclined at an angle larger than that of an opposite wall with respect to a vertical line of tread. 
     
     
       6. A large-sized pneumatic radial tire as claimed in claim 5, wherein said wall of the groove to be reinforced has an angle of 10°-45° inclined with respect to a vertical line of tread. 
     
     
       7. A large-sized pneumatic radial tire as claimed in claim 1, wherein said reinforcement is a step-like protrusion provided on said wall at kicking-out side of the tread groove to be reinforced. 
     
     
       8. A large-sized pneumatic radial tire as claimed in claim 1, wherein said reinforcement is provided on said tread groove at a length corresponding to at least 20% of the length of its groove edge having a substantially straight line.